This is a revision of a competing continuation application to collect additional longitudinal data from a panel of privately funded addiction treatment facilities throughout the U.S. At a national level, considerable resources are being devoted to bridging the "research to practice gap" in substance abuse treatment. There have been important recent developments in both pharmacological and behavioral therapies for addiction treatment, but relatively low levels of adoption by the field. Additional treatment technologies are in the development pipeline. The effectiveness of these development efforts is limited by the effectiveness with which these technologies are diffused to the field, widely implemented, and appropriately used. There are a number of organizational, environmental, and human factors that may facilitate or impede the adoption of evidence-based practices in substance abuse treatment. This study proposes to continue data collection from a nationally-representative sample of N=400 privately funded (for-profit and non-profit) treatment centers. Data obtained from both organizations and counselors in 1999-2004 indicate that the private treatment system is dynamic, and that program behavior is particularly subject to both internal (resources, philosophy, counselor turnover) and external (payor demands, competition) factors that constrain decisions to adopt new treatment approaches. We propose two additional waves of on-site data collection with these centers, complemented by two waves of questionnaire surveys of the centers' addiction counseling staff. These interviews and surveys will measure adoption and implementation of a host of evidence-based treatment practices, including pharmacotherapies and numerous behavioral therapies endorsed by NIDA. An additional focus will be to measure continued change in the organizational structure, staffing, and management of these facilities. While continuing to measure adoption of behavioral and pharmacological therapies assessed at previous waves, we include newly emerging treatment approaches as well as established "best practices" for program management. Interviews and questionnaires will assess reasons for resistance to adoption of these techniques, the extent to which various techniques are actually used, and the fidelity with which a specified set of behavioral therapies are implemented. With prior data, the proposed study would provide a total of 10 years' data on the adoption and implementation of evidence-based treatment practices in a substantial segment of the treatment system, and 15 total years of data on organizational transformation.